I believe the correct answer from the choices listed above is option D. Catalysts lower the activation energy of a chemical reaction. It <span>is a substance which speeds up a reaction, but is chemically unchanged at the end of the reaction. It provides another pathway for the reaction to occur.</span>
Answer:

Explanation:
Hello,
For the given chemical reaction:

We first must identify the limiting reactant by computing the reacting moles of Al2S3:

Next, we compute the moles of Al2S3 that are consumed by 2.50 of H2O via the 1:6 mole ratio between them:

Thus, we notice that there are more available Al2S3 than consumed, for that reason it is in excess and water is the limiting, therefore, we can compute the theoretical yield of Al(OH)3 via the 2:1 molar ratio between it and Al2S3 with the limiting amount:

Finally, we compute the percent yield with the obtained 2.10 g:

Best regards.
This is more of a physics explanation, but here we go.
Mass is a measure of how much "matter" is in an object. Weight is the force applied onto an object by gravity. Weight itself can be related to mass like this:

where g is a gravitational constant. For our purposes, it's defined by whatever planet you are on. Following this, we can demonstrate that mass is NOT the same thing as weight if we take two objects of the same mass and put them on different planets.
Let E refer to Earth and F refer to Mars

Following this, we can see clearly that weight is not the same as mass:

If weight was the same thing as mass, the two values would be the same, as the mass of the two objects is the same. But since weight is defined in the context of gravity, they are not.
Mols CuSO4 = M x L = 1.50 x 0.150 = 0.225
<span>mols KOH = 3.00 x 0.150 = 0.450 </span>
<span>specific heat solns = specific heat H2O = 4.18 J/K*C </span>
<span>CuSO4 + 2KOH = Cu(OH)2 + 2H2O </span>
<span>q = mass solutions x specific heat solns x (Tfinal-Tinitial) + Ccal*deltat T </span>
<span>q = 300g x 4.18 x (31.3-25.2) + 24.2*(31.3-25.2) </span>
<span>dHrxn in J/mol= q/0.225 mol CuSO4 </span>
<span>Then convert to kJ/mol
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